Hi,
After successfully building Rams head vero, I didn't like the sound at all, it just sounded processed, boring and harsh.
So I transformed it in to a Green Russian.
Link: http://tagboardeffects.blogspot.com/2012/06/ehx-green-russian-big-muff.html
Anyway, the problem is volume, it is INSANELY low on max, like completely low with my 15w amp turned up to half. Bypassed sound, works and is 100 times louder compared to the pedal on, vol max.
I replaced every part that needed to be replaced (resistors, caps, moved diodes in correct place) except the 3 caps, those little ones 500p. I left 470p from rams head, I didn't think it would make a difference.
Pots are from the rams head build, 100k log, where as on green russian pots should be 100k lin.
Could this be the problem, if so why?
Transistors are 2N5089.
I measured the voltages and they appear okay to me, emitters on Q2, Q3, Q3 look suspicious though...
Q1 (upper left corner)
E: 1.21
B: 1.78
C: 3.61
Q2 (down left corner)
E: 0.09
B: 0,60
C: 3.74
Q3 (upper right corner)
E: 0.03
B: 0.61
C: 3.67
Q4 (down right corner)
E: 0.04
B: 0.61
C: 3.72
What do you think the problem might be?
Could it be that those little 470p are making this problem?
Or can a short make a problem, not that I saw one, but is it possible for circuit to be shorted and still work on insanely low vol and show voltages?
Or even those pots? which I suspect the most.
Thank you.
P.S. I kept the wires from pots, switches, jacks soldered to the PCB during the modification, so wiring is most likely not a problem.
Upload some pics of the board I reckon.
Something like that happend to me, too. There was a pair of resistor with wrong value.
Check the orientation of the transistor, but more than else check every single part you have replaced.
If you can't solve, try to turn back to the ram's head until you find out the mistake.
The 500-470pf caps don't change the volume, but those change a bit the eq. If you want see how works some parts you could use socket pins for the critical parts of the several Big Muff schematics.
Quote...moved diodes in correct place
Curious about this statement.
Quote from: chuckd666 on November 12, 2016, 09:21:47 PM
Upload some pics of the board I reckon.
Alright :)
(http://i1360.photobucket.com/albums/r651/arminsalihovic/20161113_141936_zpsgag58t8p.jpg)
Quote from: Elijah-Baley on November 13, 2016, 03:35:23 AM
Something like that happend to me, too. There was a pair of resistor with wrong value.
Check the orientation of the transistor, but more than else check every single part you have replaced.
If you can't solve, try to turn back to the ram's head until you find out the mistake.
The 500-470pf caps don't change the volume, but those change a bit the eq. If you want see how works some parts you could use socket pins for the critical parts of the several Big Muff schematics.
I'll double check all the resistors... Transistor orientation is good, I think voltages are okay as well, need confirmation on that from someone.
Nobody told me if pots are the problem? I kept the pots from rams head (100k log) but according to the green russian's vero I should've put 100k lin?
Quote from: EBK on November 13, 2016, 06:40:32 AM
Quote...moved diodes in correct place
Curious about this statement.
Position of all 4 diodes is not the same on rams head and green russian's vero.
QuotePosition of all 4 diodes is not the same on rams head and green russian's vero.
But the vero layouts are the same? Did you use the linked layout? If not, I wouldn't mind comparing them. I really suspect this will be a second pair of eyes fix....
The pots are not a problem.
Quote from: EBK on November 13, 2016, 08:42:43 AM
QuotePosition of all 4 diodes is not the same on rams head and green russian's vero.
But the vero layouts are the same? Did you use the linked layout? If not, I wouldn't mind comparing them. I really suspect this will be a second pair of eyes fix....
Side by side comparison:
(http://i1360.photobucket.com/albums/r651/arminsalihovic/1_zpsldtj8d9v.png)
Did you also move the corresponding 100nF cap?
Quote from: EBK on November 13, 2016, 09:02:12 AM
Did you also move the corresponding 100nF cap?
All 100n caps are moved to correct positions.
there seems to be, from looking the photo, a cap missing between "Volume 3" and the C of the top-left transistor. is it there but obscured?
Quote from: duck_arse on November 13, 2016, 09:20:30 AM
there seems to be, from looking the photo, a cap missing between "Volume 3" and the C of the top-left transistor. is it there but obscured?
Good eyes!! :icon_mrgreen:
Even though I checked 20 times to see if something is missing I missed that...
I will install it and let you know in the next hour.
Thank you!! :icon_mrgreen:
Hi,
Fixed it! thanks! It works.
But now, I have 2 other problems...
1. Signal drops and rises a bit in volume every 2 secs or so, especially in low E, when all strings played together really noticeable. Inconsistent signal.
2. Hum... I didn't have this problem with rams head, anyway the hum sounds like wind sound caught on camera, like a pedal being connected to a really bad power supply (I ran the pedal with 9V battery).
The hum is sensitive to the sustain pot.
Same amount of hum is also present with the guitar volume pot off.
I also noticed odd sounds when tapping the wires that come out of the board.
Any ideas?
Possible broken trace (phenolic resin boards do not like soldering rework). Just a wild guess though.
I found out that input wire was making weird noises, so I replaced it, nothing is fixed. Odd sounds still come out when input wire is touched, tapped
Does the solder joint move if you wiggle that wire?
Quote from: EBK on November 13, 2016, 12:52:18 PM
Does the solder joint move if you wiggle that wire?
Okay. Input wire is okay, input wire was touching this one cap while tapping it. When I tap the cap (left corner above 100R resistor, sound gets inconsistent and cuts) so I think it might be a bad cap. I will put a new one
The electrolytic cap? I believe those shouldn't (can't?) be microphonic (written with complete deference to someone who wants to say otherwise). Check to see if the copper under it has lifted.
Make sure the transistors aren't loose and causing a bad connection. Use a magnifier of some sort to check your soldering and small hairs. Sometimes a joint looks good until it's magnified, then you can see a lead just sitting there, happens to me when I use vero. Check all the usual shorting places, wiring on enclosure, backs of pots, vero touching enclosure, etc...
Sent from my iPhone using Tapatalk
Quote from: jimilee on November 13, 2016, 05:36:03 PM
Make sure the transistors aren't loose and causing a bad connection.
What he said...!!! :icon_wink:
Thank you guys for being nice and helping me out, I got rid of the big muff I made and learned that vero isn't good for resoldering.
I have few more questions.
I got a PCB from pedalparts.co.uk and there is something called a CLR resistor? Is it some kind of a special type of resistors or I can just use a regular resistor?
And can anyone tell me if capacitors make a noticeable difference in sound?
Quote from: khm9 on November 17, 2016, 05:12:56 PM
Thank you guys for being nice and helping me out, I got rid of the big muff I made and learned that vero isn't good for resoldering.
I have few more questions.
I got a PCB from pedalparts.co.uk and there is something called a CLR resistor? Is it some kind of a special type of resistors or I can just use a regular resistor?
And can anyone tell me if capacitors make a noticeable difference in sound?
Can you provide a link for your new board or a pic?
As for caps.... It depends... Are you talking about different materials? Different values? Different ratings? Also depends on what they are being used for in the particular circuit. You have to narrow that question down a bit.
Sorry the vero didn't work out for you this time. The epoxy kind is more forgiving that the phenolic resin kind you used. Give it a try if you ever decide to try vero again.
The CLR is probably just a "current limiting resistor" for an LED. Just an ordinary resistor.
CLR resistor is a Current Limiting Resistor usually associated with an LED.
*edit* EBK beat me to it.
Of course, nothing stops you from coating it in opaque epoxy to make it look like a mysterious mojo part when you show off your finished build. :icon_wink:
Quote from: EBK on November 17, 2016, 05:38:59 PM
Quote from: khm9 on November 17, 2016, 05:12:56 PM
Thank you guys for being nice and helping me out, I got rid of the big muff I made and learned that vero isn't good for resoldering.
I have few more questions.
I got a PCB from pedalparts.co.uk and there is something called a CLR resistor? Is it some kind of a special type of resistors or I can just use a regular resistor?
And can anyone tell me if capacitors make a noticeable difference in sound?
Can you provide a link for your new board or a pic?
As for caps.... It depends... Are you talking about different materials? Different values? Different ratings? Also depends on what they are being used for in the particular circuit. You have to narrow that question down a bit.
Sorry the vero didn't work out for you this time. The epoxy kind is more forgiving that the phenolic resin kind you used. Give it a try if you ever decide to try vero again.
Hi EBK, thanks for replying :D
here is the link to the pdf, its a delay circuit based on mad professors deep blue delay
http://pedalparts.co.uk/docs/EchoBlue-v3.pdf
As for the caps,I am talking about different quality.
I thought rams head sound was bad so I changed the pcb to a green russian, changed the character but not the core sound which remained the same. Can't be that both versions were bad. It must've been the components.
It definitely had its green russian feel but sound just wasn't right, nor was it right for rams head, it just sounded horrible, it sounded like a fuzz, but not like big muff I am used to. The sound was just not right, close, but not right. Those box type caps were ordered from tayda, and resistors were from a huge ebay kit, were $10, anyway, I guess it were the caps that ruined the tone, didn't give it the proper big muff sound, especially those box type ones are suspicious to me...
And resistors should not make an audible difference right? Tayda ones are good enough?
Also one thing that really annoyed me during the life of the green russian was the placement of the pcb, it kept moving inside, any good ideas on how to fixate the pcb on top of the pots, but not permanently?
I sure won't worry about that with this PCB I got since pots get soldered on directly! :icon_mrgreen:
Quote from: EBK on November 17, 2016, 06:19:39 PM
Of course, nothing stops you from coating it in opaque epoxy to make it look like a mysterious mojo part when you show off your finished build. :icon_wink:
I won't give up on vero yet, still have few of vero boards laying around and still interested in building few dirt pedals I've always wanted to try
Hmm. Well, there still isn't enough info to say why it didn't sound like you expected. I would not blame the brand of caps or resistors though. How recently did you hear the big muff you are comparing these new circuits to?
Quote from: khm9 on November 17, 2016, 05:12:56 PM
.... there is something called a CLR resistor? Is it some kind of a special type of resistors or I can just use a regular resistor?
And can anyone tell me if capacitors make a noticeable difference in sound?
me too - CLR is a current limiting resistor. value unspecified. is you have a superbright led and you wish deadastronaut to know your bypass status, use something like 4k7, around that value. if you wish to remain sighted into your old age, use 22k, or 33k, or 47k. for a dull, diffused, coloured lens type - well, try it on the breadboard. 9V - a led - a resistor. that's it. BUT ALWAYS A RESISTOR! ALWAYS!
and no-one can tell you if capacitor type makes a difference in sound (they don't. well, they also do. depends on the sound, the caps, the ears). put a circuit on the breadboard, a big muff if you will. get it working, then start swapping in and out your different caps.
then decide what you hear, come back here and start a thread on the topic, and watch the bunfight start (again. we love bunfights).
it is most often not the components, but the connections between that are problematic in pedal construction.
If you are looking for some general rules of thumb, here's my input:
1. For small values (less than 1 uF), use film caps whenever possible (like your Tayda box caps), unless you are using them for power filtering or bypass, in which case use ceramic.
2. Make sure the voltage rating is adequate.
3. Beyond that, I prioritize size and price over any other parameter (keeping the capacitance value correct, obviously).
If you ignore items 1 and 3 above, your circuit probably won't sound a lot different from mine. If you ignore item 2, your circuit might be more exciting to watch than mine. :icon_biggrin:
Quote
Also one thing that really annoyed me during the life of the green russian was the placement of the pcb, it kept moving inside, any good ideas on how to fixate the pcb on top of the pots, but not permanently?
I use double stick foam tape. You can cut it to any shape you need and stack it to any thickness.